Peta (P) is the prefix of quadrillion (1,000,000,000,000), or `10^15`. In the dual system, a petabyte has a value of `2^50`. It corresponds to 1,024 terabytes( TB) or over 1 million gigabytes( GB). 1,024 petabytes make up an exabyte( EB).
Although there are no special orders of magnitude for Big Data, size specifications in petabytes or in exabytes are to be assigned to Big Data.